


SkeleTON of Problems

by MysteryNA



Category: Undertale (Video Game)
Genre: Abuse, Fighting over the lil' skele, Fontcest, Horrible nightmares, Rape, Underfell, Undertail, dog pack, protective, sans is pregnant, skele preg, slicing womb
Language: English
Status: In-Progress
Published: 2016-03-24
Updated: 2016-07-05
Packaged: 2018-05-28 17:43:47
Rating: Mature
Warnings: Rape/Non-Con
Chapters: 3
Words: 9,049
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6338947
Author URL: https://archiveofourown.org/users/MysteryNA/pseuds/MysteryNA
Summary: <blockquote class="userstuff">
              <p>Sans becomes pregnant after being continuously raped by his brother. He tries to hide it but when his brother discovers his secret, he flees to protect his child. </p><p> Sans is a very protective mother ;)</p>
            </blockquote>





	1. Chapter 1

“Useless piece of shit!” Papyrus kicked Sans in the stomach, forcing the smaller skeleton to crumble to the floor. His brother loomed over him with a deep scowl and his eyes glowed dangerously. Sans curled in on himself to shield his damaged belly as he looked up at his younger brother.

 

“Don’t just lay there, you sack of trash. Get up and make yourself useful,” Papyrus slammed his boot down onto Sans’ stomach again, but Sans kept his arms firmly shielded over the ectoplasm belly. Whimpering, he waited for the foot to be removed before he sat up slowly, hoping to prevent any more damage.

 

Papyrus looked him over and noticed that he was being a lot quieter and was covering his stomach more so than any other part of his body. “Are you hiding something from me?” Papyrus asked darkly. Sans’ eyes faded and he shook his head rapidly.

 

“N-no Boss, i-it’s nothing. I’m fine,” He stammered as he scrambled to his feet. He stood as tall as his shaky legs would allow, and his red eyelights locked on the front door. If he could just make a dash for it…

 

Just before he could slip outside, a hand slammed the door shut just over his head and he flinched before turning around to face his towering brother.

 

“Sans… you know I hate being lied to…” His growl made Sans cower even lower, but he kept his hands wrapped around his front in case his brother lashed out again. Papyrus was quick to notice and grabbed his wrists to wrench them away from his midsection. Sans struggled against him, but his grip only tightened painfully. With one hand still holding Sans wrists, he used his free hand to grab Sans jacket to lift it. Sans cried out in urgency and tried to fight off his brother’s death grip, but to no avail. His shirt was carelessly yanked up, revealing a red glowing ectoplasmic belly and a small soul floating inside. Papyrus went absolutely still as he took in the sight of the small soul. Sans in turn went rigid.

 

They sat in tense silence, neither of them daring to say anything. As the silence prolonged, Sans started shaking uncontrollably as he waited for Papyrus to speak. Half of him feared for the small growing child and the other feared for his own life.

 

Finally, Papyrus seemed to awaken from whatever deep thought he had sunken into and ran one of his sharp fingers across the surface. Sans whimpered in fright and tried wiggling free, but the hand on his belly latched onto it tightly. He could feel Papyrus sharp nails digging into his ectoplasm casing, causing Sans to panic and only struggle even more.

 

“Sit still shithead!” Papyrus snarled venomously. He tried to work his clawed finger deeper into the new womb, but Sans refused.

 

“No… no no no…” Sans grew more desperate as tears sprung to his eyes. He didn’t want to lose the child, even if it came from his abusive brother. It was the only sliver of hope in his life and he wasn’t about to let anyone take it away. Sans’ left eye flared to life with red flowing magic and he managed to knock his brother away before teleporting in a blink of an eye without a second thought.

….

 

Sans ran blindly ahead. He didn’t care where he ended up as long as it was far away from his dangerous brother. Papyrus could call him any shitty name, hit him, despise him, and he didn’t care, but if Papyrus dared to think Sans was about to just sit still and let him kill his own child, then he was dead wrong. It wasn’t until he used up his reserve of magic that he collapsed a ways out of Snowdin in the snowy forest.

 

Normally, since a skeleton didn’t have skin, they couldn’t feel the temperature, but now that Sans’ ecto-womb was summoned, the temperature was a bitch. Curling into himself, he covered his belly in hopes of keeping his child safe and warm. He felt sleep tugging at the back of his eye sockets, luring him closer into the false promise of safety and shelter. As he closed his eyes and felt himself drift off, Sans hoped for a dreamless sleep but to his worst fears, he wasn’t so lucky.

….

 

“Sans! You pathetic little bitch!” Papyrus threw Sans into the basement below the house. It was once used as a lab but had long since been remodeled into a torture chamber. Sans pulled himself upright from off of the cold stone floor and crawled away from his brother in a panic. But the taller skeleton came up behind Sans and slammed his foot into his back, forcing Sans face first onto the ground and squishing the belly beneath him. Sans tried to wiggle free to protect the child, but Papyrus was having none of that.

 

He forcefully flipped his brother onto his back before digging his claws into the fleshy magic, ripping it open in the process. Sans cried out and tried to shove his brother off. The pain burned like nothing he ever felt before. It was pure white hot agony, both physically and emotionally. He screamed and kicked his legs frantically in a desperate attempt to force his brother off of him and away from the soul within him.

 

Papyrus growled in fury and summoned two sharp bones, slamming both of them into each of Sans palms, pinning him to the dusty floor. Sans screamed louder and tried once again to kick his brother off, but Papyrus sat down on his stomach and used his knees to painfully pin his legs down.

 

“So help me, if you struggle any more, then I will be forced to take drastic measures!” The warning was well heard and Sans went limp on the floor.

 

“Good~” Papyrus continued to trail and poke holes at the belly. Sans whimpered in pain and fear but he held still, more fearful of a worse punishment. Red ectoplasm oozed out of the holes in his stomach, coating the floor around him in the sticky substance. The sight made him feel ill, but Papyrus’ looming shadow forced him to remain compliant. He began to feel weak and lightheaded, and for a moment, he wondered if this was what it felt like to bleed.

 

“You’re so obedient!” The purred compliment made Sans' rib cage rattle in disgust but he shook it off.

 

Papyrus looked at the red liquid pouring out in interest before leaning in and scraping his teeth against the torn magic of the womb. Sans shuddered in revulsion as his brother licked up the plasm that spilled out of the penetration. Sitting back, he trailed a hand lower on his brother’s body before gripping Sans hips and yanking him a little closer so that they were face to face.

 

“Have a taste~” Papyrus leaned down and clanked his teeth against the smaller skeleton’s mouth. Sans groaned at the gesture and almost didn’t want to comply until he felt a squeeze on his belly. The feeling of the fresh ectoplasm running down his bones was enough to keep him locked in place, much to his brother's delight. He gasped as an invading tongue was forced into his mouth, followed by the bittersweet taste of the plasm. His thoughts left his mind as his tongue was wrapped around by Papyrus' and stroked.  

 

 Keeping their tongues locked together, Papyrus began to fondle Sans' pelvis making the smaller skeleton moan into the kiss and bucked his hips upward against his will. He felt disgusted at himself for the way he melted into his brother’s touch and became a slave to his hand. Papyrus hummed in satisfaction as Sans nether regions formed a slick wet pussy from his fondling. Wasting no time, he slipped a finger inside and Sans arched his back at the intrusion.

 

Worry flooded his mind and built in his chest at the thought of being fucked while carrying a child, as well as the concern of his womb being torn any more, but Papyrus paid it no mind and forced his tongue further into Sans’ mouth. Moaning louder as a second finger was added, his breath became labored and shallow. Feeling his heat beginning to pour over, Papyrus slipped his hands free, eager to penetrate his pregnant brother and taste more of his sweet fluids.

 

Angling his pulsing cock, he rammed it forward and made Sans cry out in alarm. His stomach felt even fuller and he could see the red cock glowing through his transparent belly. It was filling him to the max and he wasn’t sure he could take much more. His brother grinned wickedly at Sans panicked expression before he began thrusting in violently.

 

“W-wait! Wait! S-Stop, please!” Sans begged, but Papyrus ignored his pleas and only picked up his pace as he forced Sans legs further apart for more access. The stretch hurt, but the pain and worry was quickly drowned out by his brother’s ragged breathing and his own loud moans. Sans’ worries slipped from his mind as Papyrus’ hot breath trailed down his collarbone. The only thing he could think of was the burning sensation of pain and pleasure. He felt like his body was on fire.

 

Feeling his orgasm drawing close, he forced it down, waiting for his brother to spill first. His brother must have sensed his need because he began to relentlessly pound into him over and over again while withholding from giving in himself. Sans noticed the gleam in his brother’s eyes and he feared that his brother was testing his resolve. But the feeling of needing to cum became too painful, and he spilled over with a loud cry.

 

Before he was even given a chance to recover, he felt his brother release shortly after a few more hard pounds. Rocking his hips to further milk out the rest of his cum, Papyrus smirked in satisfaction to see his essence filling the space inside the belly, coating it in a darker red.

 

“Mine~…” Papyrus purred next to Sans’ ear and brushed his fingers along the lump. Sans shuddered at the low tone and turned his head away from him. Closing his eyes, he tried to catch his breath and shut out the aftereffects, until he felt himself being lifted off the ground. Sans flinched and opened his eyes in a panic, but was powerless to do anything as he was thrown into a chair facing the wall and strapped down.

 

“My dear brother…” The cold tone put Sans on high alert. It usually meant he was going to receive a punishment. “You came before me… and I thought you were well trained…” The mock disciplinary voice had Sans soul plummeting down. “Now I must punish you…” Papyrus walked out of Sans view and he tried desperately to follow him with his eyes but he couldn’t turn his head far enough. Straining his ears, he listened for his brother’s footsteps as he walked around behind him. After a few minutes of pacing, Sans turned to stone by the clanking of metal followed by the sound of two blades being drawn against each other.

 

As his brother came back into view, he was holding a towel and a knife.

 

“Sit tight, I want to make this as painless as possible.” Sans paled as the knife was lowered to his belly. He wanted to scream, to force his brother away from his already damaged womb, but his nonexistent lungs refused to build up enough air. Slowly, the knife started to press more firmly into the soft flesh.

 

Sans tugged at his restraints, and lurched around in his seat, hoping to free his arms or to do something, anything but the bindings held. Sans screamed in horror and pain as the point of the knife dipped into the top of the belly and slowly, tauntingly slowly, sliced him all the way down to the bottom. The ectoplasm within his belly started to pour out of the open gash and spill onto the concrete floor. Withdrawing the knife, Papyrus wiped it down on the cloth before kneeling in front of Sans with a soft smile.

 

Sans sobbed with distraught as he watched his fluids drain out. Papyrus cooed softly and ran a soft hand across Sans cheek to wipe away the tears as if trying to console him but Sans pulled away defiantly. Papyrus’ expression hardened, and he firmly gripped his brother’s head in one hand, forcing him to face him.

 

“You should really learn your place.” The indifferent tone had Sans freezing up and he watched with more agony as Papyrus’ free hand grabbed at the folds of the womb and tugged them back, forcing the liquid to drain out faster. He knew he was powerless to do anything, so his head hung low in defeat. However, he shrieked and jolted as his brother slipped his hand inside his womb and latch onto the small soul.

 

Papyrus could feel the soul twitching and shaking in his grasp as he carefully tugged it out and brought it up to eye level. Sans could only watch in despair as the last of his ectoplasm drained out, leaving only the small defenseless soul in Papyrus' care.

 

“Such a pity you weren’t trained better. Perhaps next time you will be more behaved.” With a rough squeeze, the soul burst into dust and fluttered to the ground. Standing up, Papyrus didn’t even bother to untie his brother before turning to leave. Just before he exited, he called down the stairs, “Sit and think about what you’ve done. I’ll come by tomorrow to check on you. Hopefully by then you’ll have learned your lesson.” With a slam, the basement door was forced closed, and Sans was left to stare down at the red sticky floor and what was once a baby monster soul but now was just a small pile of dust at his feet. Hanging his head low, he cried out his pain to the empty walls, the sound bouncing and echoing back almost mockingly.

…

 

Sans shot awake in a panic and ran his hands across his belly in worry. His nerves calmed slightly as they touched the familiar warm magical barrier. His head was covered in sweat and he felt extremely weak from sleeping out in the cold. Standing up onto stiff legs, he realized that his belly was far colder than it should be. The baby could die! He wouldn’t let that happen! Summoning his magic, he hoped to transfer some heat to the baby inside and keep them as warm and healthy as possible.

 

Wrapping his arms back around his front, he trudged through the snow, making his way back towards Snowdin and the warmth of Grillby’s. After that dream, a new determination filled Sans soul. He would be damned before he let his brother even a hundred feet of HIS child!

…..

 

Sans was still a good ways out, but he could already smell the delicious aroma of Grillbys’ and he picked up the pace towards the diner. That was until he sensed danger nearby and narrowly dodged a lunging dog monster. He recognized the monster to be Greater dog. Following behind Greater dog came Doggo and Lesser dog.

 

Great… the dog pack was out scouting the forest. Just his luck... Sans summoned his red aura and snarled at the pack, showing off his golden tooth and making his aura radiate a warning.

 

The pack slightly hesitated, not used to Sans putting up such a defensive front.

 

“What happened shitface? Did you get into a fight with your brother and came out here to mope like a bitch?” Quipped Lesser Dog.

 

Doggo snickered and followed up with his own insult. “Or perhaps your brother finally disowned you!”

 

“Heh heh…” Sans cracked his knuckles. “Hardly!” Summoning a ring of bones around himself, he faced them all outwards acting as both a defensive and offensive ability. The dogs all glanced at each other feeling unsure at the smaller skeletons sudden burst of confidence.

 

Deciding to test the waters, Doggo lunged in this time. He had the fastest reaction time to movement and could get out of the way a lot faster than his pack mates.

Sans wasted no time hurling one of the bones at Doggo who expertly ducked away from it and kept his charge, dodging each proceeding bone until he was within a death strike and he took it.

  

Sans smirked at his opponents ignorance as the bones came flying back in, aiming for Doggo’s exposed backside. However Doggo realized just a moment sooner and managed to slip away but not without first getting a nasty nick in his shoulder. The dog yelped and jumped away before turning his head to nurse his shoulder with his tongue.

 

The other dogs all circled Sans with a frustrated growl. It wasn’t until they heard a loud howl that they all paused to listen before howling back. Sans shuffled nervously. They were calling the rest of the pack. It was now or never if Sans wanted to get out unscathed, so he darted toward Snowdin. The dogs stopped their howling to bark in excitement at the prospect of a chase.

As Sas ran, the dogs took turns snapping at him but they were all moving in predictable patterns and he was able to easily dodge. Each time one of them got to close for comfort, he would summon a barrier of bones before slapping their snouts with a bone but this fighting pattern would only hold off their attacks for so long.

 

As they neared Snowdin, Sans began to slow. He was losing stamina and magic power quickly. He was far too exhausted to attempt another teleportation, and he couldn’t run any longer, so he slid to a halt and put back up his defensive ring. The dogs all slid in behind him. Both excited and sad that the chase was over.

 

Glancing back, he could just barely make out the top of the inn. He knew trying to sprint the rest of the way would only result in a decisive blow by the pack so he would have to wait them out until he found an opening. Only problem, Dogaressa and Dogamy broke through the trees.

 

“You weren’t planning on (starting the party without us) were you?” The pair spoke in unison.

 

“‘Course not!” Greater dog replied with excitement. They were finally going to kill one of the skelefuckers! Now that they were a pack of five, Sans counted the odds against him. Especially since Dogaressa and Dogamy were known as the most powerful duoing pair.

 

“(Was this little skelepup) causing you three problems?” Doggo, Greater dog and Lesser dog all looked down shamefully at the snow.

 

“He was being a lot more stubborn than usual.” Doggo added quietly.

 

“Was he…?” The two mates looked Sans over before Dogaressa stuck out her snout and gave a large whiff of the air.

 

Realization stuck and she pulled back with a smirk. “(Well well well, what do we have here?)”

Dogamy looked at his mate quizzically.

 

“(So how far along are you?)” Cooed Dogaressa.

 

Sans remained quiet, refusing to relent any information. He could already feel sweat beading on his forehead in worry.

 

“Please my love, explain what you mean.” The other three dogs also looked at her curiously.

 

“(This little skelepup grew up and became a mom.)” She teased with a low rumble. The other dogs took a moment to understand before they barked out laughing.

 

“So he is a bitch then!” Greater dog rolled onto his side laughing and Sans’ eyes darkened at the comment but he otherwise remained guarded. For a split second, he considered making another break for it but Dogamy reacted fasted and successfully lunged at Sans, pinning him to the ground. His snout was inches from his face as he stared down into Sans’ fearful eyes.

 

“Looks like you used up all your magical reserves.” Sans stared into Dogamy’s black pupils with a sinking feeling. He was going to die… Closing his eyes, he accepted his fate. At least he would die with his child instead of being left behind. He could already feel the dog's hot breath closing in on his neck.

 

“(Not so fast dear…)” Hearing Dogaressa’s call, her mate paused.

 

“What ever is the matter dear?”

 

“(The reason for his change in hostility is because of his mothering instincts.)”

 

“The slutty bitch actually cares about that bastard of a child?” Snickered lesser dog. Dogaressa lashed out at him with her paw, swatting him upside the head. Lesser dog immediately fell silent rubbing the sore area.

 

“(A mother is still a mother.)”

 

“Sooo? What are you suggesting?” Doggo asked impatiently. “We’re not letting him go are we?”

 

“(Not quite…)” Dogaressa trotted over to Sans and Dogamy who still had him pinned at the front. Leaning down, she nuzzled Sans belly in interest. The magical barrier was warm to the touch and she could see the soul inside withdraw in reaction to Sans own fear. Catching the stubby skeletons eye, she could see panic and protectiveness flashing across his features.

 

“(I say we keep him.)”

The pack all went silent in surprise at the suggestion.

 

“Keep him?” Dogamy looked at his mate trying to understand her reasoning,

 

“I am not a pet!” Sans growled out angrily. Drawing all the attention back onto him.

 

“(Just think about all the benefits. You’ll get to stay fed and warm, away from danger and I can help you nurse your child!)”

 

“Thanks but no thanks! This child is mine alone!” Satisfied that he had saved up enough magical power in that short duration of time, two bones protruded out of the earth, knocking the dog pair away. He wasn’t strong enough to make the bones actually lethal, but they were enough to put some distance between them. He decided it was now or never and he made a break for the Inn.

 

The dogs only needed a second to realize what had happened before they started back up the chase. They caught sight of the Inn and knew they had to act fast or else he was going to get away. Instead of attacking in a pattern, they all lunged at once. He was able to ward off three of them, but the fourth, Dogaressa knocked him into a tree and he hissed in pain as his spine got wedged into the trunk and it nearly shattering his weak soul. He could feel his single HP drop a fraction.

 

“You really (shouldn’t have run!)” The pair snickered in unison. “We were only (trying to help.)”

 

“I don’t want your help!” Glancing back towards town, he could see the front of the Inn now. He was so close…

 

“Such a pity.”

“(It’s rare to find monsters who care so much down here…)” He could hear the parting words mixed into their meaning and he shuddered at the thought of dying.

 

“Make it quick!” They were more than happy to oblige as their teeth closed in on his neck. Taking one last breath, he slumped into the tree, accepting his fate. Suddenly, the teeth on his throat were gone and he heard a loud yelp of pain. Opening his eyes in surprise, he caught sight of a barrier of bones surrounding him and a few more leveled towards the pack. Out of the trees stepped Papyrus who looked beyond furious.

 

“Who said you could kill my brother!” Papyrus strolled forward with his power at max output.

The dogs all backed away fearful of the royal guard leader.

 

“Leave! Or so help me, I will turn you all to dust here and now!” Heeding his warning, the pack all turned and fled. He waited before they were gone before turning back to Sans who had since passed out. His body was cold and battered and his HP was barely dwindling at ½ health. He knelt down next to his brother and tried to lift him up but when he was unable to budge him, that was when he noticed his spine was stuck. Summoning a sharp bone, he chipped away at the wood, careful not to accidentally nick Sans and extinguished the last remaining health his brother had. Once the spine was freed from its prison, he lifted Sans gently into his hands and set off for home.

 

As Papyrus walked back to their house, he noticed Sans shirt was slightly pulled back revealing the red womb and with a gentle hand, he caressed the surface only to feel it extremely cold. Transferring some of his power over to his brother, he felt his body warm slightly.

Stepping through the front door, he trudged right to his brother’s bedroom but stopped at the sight of it. Trash, stray socks and other strewn about objects covered the floor and his bed was bare without any sheets or blankets. Withdrawing from the room, he carried Sans over to his own room and gently laid him down on the soft mattress before pulling up the covers and tucking him in.

 

His gentleness was very uncharacteristic, but right now, he was far more worried about his brother’s well being to let it bother him.

 

Heading downstairs to the kitchen, he started prepping dinner to get some substance into his weak brother. He felt guilt over take his senses and he transferred his emotions into his firm chopping. He had starved his brother over the last week and now that he knew Sans was pregnant, he worried he might have just killed their child… The last thing he expected was for his abuse to bring about a new soul into the family… should he just flush it out and try again? Was having a child even a good idea? Reflecting back on it, Sans was being very protective of his belly. Perhaps he wants to keep it…

 

Shaking off the thoughts, Papyrus focused back on dinner. His vegetables were chopped rather than mashed. Shrugging, he dropped them into a pot of water and turned the stove onto medium before making his way upstairs. Stepping into Sans’ room, he set to work cleaning up the mess.


	2. Chapter 2

**Notes for the Chapter:**

> I might have quite a few spelling and grammar errors. If so, let me know and I will go through and correct them. :)

Sans woke up groggily. His eyelids felt heavy and his head was pounding so he just left his eyes closed. Groaning, he sat up in bed and gently ran his hands over his belly and sent his energy to the soul inside. Since his brother had forbid him from eating, he had to find another solution to fed his child, so he just used his own life energy. It made him more tired and weak but at least the soul would live… unless he died before it was born. Giving up his energy basically tripled the effects of starvation.

Stretching out his arms and back, he felt his joints pop and he sighed as the tension was released. Dropping his hands back down to his side, his fingers brushed along a soft material and his brow creased in confusion. Opening his eyes, he stared down at the red and black sheets and blanket. His confusion turned to surprise and he glanced around the room to confirm he was sleeping in his brother’s room. Jumping off the bed, Sans rushed out the room only to ran into his brother. Sans fell forward, while his brother stumbled backwards. With a yelp, they both tumbled down the stairs. Papyrus cursed and tightly wove his arms around his brother. With a painful grunt, they landed on the bottom step. Sans was laying on top of Papyrus and he quickly scrambled off in a panic.

“B-boss?” Reaching out cautiously, he ran his hand over his brother’s head hoping to soothe the pain. Sans’ soul dropped as his fingers brushed along a few cracks in the skull. He was already tired from transferring his energy earlier but he pushed through his exhaustion to heal the cracks. His soul started to break under the overuse of magic, but he didn’t care. While his brother might not treat him the best, he was still his brother and he wasn’t about to let him turn to dust. As soon as the last crack was sealed over, he collapsed onto the floor, feeling darkness overtake his senses.

…..

Papyrus sat up feeling his bones aching. The last thing he remembered was his brother suddenly rushing out of his room and knocking the both of them down the stairs. Cracking his neck, he eyed his surroundings to find he was still at the bottom of his stairs. Looking down, his eyes fell onto his brother’s still form and he rolled his eyes. Standing up, he nudged his foot into his brother’s side.

“Get up lazy ass! Falling down the stairs shouldn’t have made you pass out weakling!” When he didn’t receive a response, he kicked him harder. “Get up!” He growled out with frustration. Nothing. Hissing under his breath, he knelt down and push his brother over. “Don’t make me tell you aga…” Papyrus stared in horror. Sans’ soul was covered in cracks and was slowly starting to turn to dust.

“No... no no no…” Papyrus careful lifted his brother off of the ground and cradled him to his chest as he bolted out the door, running towards the river person to get a ride over to Alphys’ lab. As he ran, he transferred his energy hoping to slow down or stop the soul breakdown.

He didn’t even spare a single word with the river person as he jumped onto the boat. They seemed to already have an idea of where he needed to go and the boat was off drifting down the river.

He had never been so panicked in all of his life. Suddenly, he remember the child and he carefully pulled up his brother’s shirt to see the small soul inside darting around furiously.

“You’re lucky.”

Papyrus broke out of his thoughts and he glanced over at the river person. He wasn’t entirely sure he had heard correctly.

“Excuse me?”

“You took a nasty fall. You’re brother saved your life.”

“He what!?” Looking down at Sans, he wasn’t entirely sure what to think or feel… and wait…

“How would you know?”

Instead of answering, the river person continued to talk. “The child is very powerful.”

“The child…”

“A soul born of the most powerful monster in all of the underground. But beware…”

Most powerful monster in the underground? Surely the river person was referring to him, but was he truly that powerful? The idea excited him. And what did they mean by beware? As they pulled up on the shore of Hotland, Papyrus didn’t even bother to thank the river person for the ride as he bolted for the lab.

Reaching the heavy metal door, he pounded on it roughly. When he didn’t receive an immediate response, he pounded again.

“Alphys!”  
He heard a grunt of annoyance on the other side before the shuffling of feet moved towards the door. As soon as the click of the lock was heard and the door cracked open, Papyrus shoved his way through.

“HEY!” Alphys snapped angrily. “You can’t just…” Her words trailed off as she took in the state of Sans’ limp form and Papyrus’ panicked expression. “What happened?” Her aggression immediately dissipated and she got straight to business.

“Sans’ is dyin, you’ve got to help him!” Papyrus demanded with a mix of authority and pleading. It was an odd mix but Alphys could hear the desperate cry behind his words. While she might care less about the skelebros, she still feared going against Papyrus and hearing his voice lowered to suck a degree of weakness soothed Alphys’ bitter feelings towards the skeleton. She could just envision Undyne being in Sans position and she herself was seeking out help, only to be rejected. She couldn’t subject the royal guard leader to such a cruel rejection, so she opted to help them out.  
“You know I’m not that type of doctor…” It wasn’t a question, nor was she turning him down, she just led the way deeper inside the lab and Papyrus followed silently behind. Taking the elevator down, they stood in tense silence. Papyrus’ gripped his brother tightly to his chest, while Alphys fiddled with her glasses. As the doors opened, she hurried forward and led them into her examination room. The room was usually devised for experimentation on specimens but it was the best room to fit her needs for an actual patient.

“Lay him on the table.” She instructed. Papyrus carefully lowered his brother to the cold steel table and stepped back to get out of Alphys’ way and she hurried around him bringing a mix of equipment over.

“You still haven’t explained how he got like this... “ Alphys’ said offhandedly as she worked.

Papyrus grinded his teeth in frustration that she hadn’t let it go, but she at least deserved an explanation if she wanted to help his brother to the best of her abilities. “He was attacked by the dog pack... after dealing with those mutts, I put him in bed and was busying around the house when he came rushing out of the room in a panic and we both feel down the stairs…” God this was humiliating. “I blacked out and when I came to, Sans was like this. I don’t know much else beyond that…” If Alphys was judging him or not, he couldn’t tell, she remained quiet throughout his explanation and hadn’t shown much signs of really caring.

After a few moments of silence, Alphys clicked her tongue in thought before speaking. “I am hooking him to the monitor to check his magic levels.” Alphys bend over the examination table and unzipped the front of Sans’ jacket before she lifted his undershirt to get access to his ribcage below the articles of clothing. As soon as she glanced at his belly, she paused and her mouth hung open in surprise. Her body froze. Turning slowing, she faced Papyrus with a skeptical look.

“Here’s something you’ve forgot to mention…” Alphys gestured towards the red womb and the small soul that glowed inside. “When and how did your brother get pregnant?”

Papyrus tsked in annoyance. “That is none of your concern!” He hadn’t meant to snap at the monster that was saving his brother’s life, but his regret made him antsy.

“Excuse me, but this is an important matter to discuss if you want me to help you!” Alphys snapped back with equal frustration.

Grumbling, he folded his arms and looked away before complying. “I… raped him…” Papyrus said quietly.

“What was that, I didn’t quite hear that.” Papyrus glanced over in Alphys direction to see her staring him down.

Clenching his teeth tightly, he let his anger boil over before simmering down as he reminded himself that this was because of his own fucking stupid fault. “I RAPED HIM OKAY!” Papyrus shouted at the top of his voice. Alphys looked taken aback by his outburst and she readjusted her glasses.

“I see…” She responded slowly.

“I don’t know how long he’s been pregnant, I just found out today! The last I raped him was three days ago…!” Papyrus bit off the words towards the end and tightened his hands around his arms in an attempt to hold himself together. He felt shivers course through his bones and tears threatened to spill over. At the very least, he would not let himself cry in front of Alphys, so he summoned his tongue and bit into it painfully to distract himself.

Alphys turned her attention back to her patient quietly as she hooked up the cords to Sans soul and rushed over to the machine to check his readings. The second her eyes scanned over the monitor, she gasped audible in surprise. Papyrus was at her side in a second, concern plastered over his face.

“What’s wrong!”

“T-these readings, they’re off the charts!” Alphys scanned over them again, making sure she’d seen it correctly.

“What do you mean?”

“His soul is very weak and his magic is spent, but right now I am measuring his maximum magical output and it is beyond the normal capacity of any monster I’ve seen…” Alphys began running her clawed finger across the screen as she triple checked the readings.

“My machine is not wrong… his magical power is so powerful and intense that it is affecting his overall health. His power is breaking apart his body and reforging it at an endless, impossible rate, resulting in the monsters constant single HP, that would also explain his constant state of fatigue. With this much power, he should rightfully be dead but his body is acting like a dam. It is withholding the power, while only letting a small stream of power to slip through so as to not cause the body to self destruct. So he must be constantly using magic none stop. If he were to let his power out in one large surge, he could potentially wipe out the whole underground.”

Papyrus’ soul quivered as the words of the river person sunk in. The child born of the most powerful monster in the whole underground… so he wasn’t referring to Papyrus, but to his brother… What did he mean by be warned…?

“I am going to check the readings of the child's soul next.” Alphys rushed back to Sans’ side and unattached the cords from his soul before reattaching them to his belly. In less than a minute, she was back at the monitor.

“I don’t believe this!” Alphys looked towards Papyrus with wide eyes. “The baby’s soul is feeding off of your brother’s life energy! It’s barely even a few days old and it’s magical energy is already surpassed even some of the most powerful monsters in the underground…” Papyrus’ mind blanked out at the new information. He couldn’t comprehend everything he was learning. His brother was far more powerful than he thought, his… their child was far more powerful than most monsters and it’s only inside the womb… it’s feeding off of his life energy! Papyrus head spun and he had to catch himself on the wall to remain upright.

Wait… life energy… “Alphys…” His concerned tone had her whipping her head away from the screen with interest. “You said it’s feeding off of his life energy…” At first she paused and then her expression turned to panic.

“Papyrus, if you want your brother alive, then we need to get this child out of Sans immediately! His single HP and constant flow of magic, along with the burden of carrying a child is going to destroy his body!” Not giving Papyrus a chance to consent or argue, she darted out of the room.

Papyrus stared after her before focusing on his brother’s limp body. Walking around the table, he stared down at the red glowing barrier shaping Sans belly and gently caressed the warm surface. Sensing his presence, the soul inside glowed warmly and with a gasp, he felt a spark of connection resonate within his own soul in response.

Papyrus jerked away as Alphys returned to the room carrying an incision knife and a few towels.

“What was those for?” He asked carefully. Alphys gave him an unreadable stare before responding.

“We need to flush out the soul.” Lowering the knife to the top of the womb, she pressed down gently to ensure she'd make a clean cut before Papyrus grabbed her arm and pulled it away.

“What are you doing!?” She demanded angrily.

“There has to be another way…”

“What other way!? Your brother is dying and you want to waste time thinking up solutions!?”

“YOU’RE THE SCIENTIST NOT ME! SO FIGURE IT OUT!”

Alphys inhaled sharply and pinched the ridge of her nose. “You’ve bonded with the soul, haven’t you…” It was more of a statement but Papyrus slowly nodded anyways. Breathing out slowly, she looked down at the belly. “Fine… I will see what else my readings can find.” Lowering the blade to the side, she grabbed a couple different tools and began prodding them at the belly gently. Papyrus waited with tense eyes.

“I can’t focus with you hovering over me like that. Go and make yourself useful elsewhere. I will see what I can find and I’ll do what I can. Once I’m done, I’ll come looking for you.” Alphys waved him off and Papyrus growled at her commanding tone but he let it go. He couldn’t stand all this waiting and watching, so he decided he might as well do his runs and distract himself.


	3. Chapter 3

**Notes for the Chapter:**

> Whelp, here it is. I finally finished the third chapter. I apologize for the wait. My biggest focus right now is my other story, but I decided to sit down and finally finish this chapter. This chapter was probably the longest I'd ever spent writing in small intervals. Again, please let me know if you see any spelling or grammar errors, one or two always seem to slip through.

 

 The second Papyrus was out of her way, Alphys squealed with glee. She couldn’t believe it. A monster this powerful was living right under her radar, completely undetected and unsuspected. She’d never once considered Sans to be anything but useless baggage to the powerful and threatening Papyrus. She’d often wondered how one brother could turn out so right and the other so horribly wrong. Now she realized how amiss she was. Sans was the ultimate monster. His power far surpassed his brothers and with that kind of power, she could easily break the barrier, free all the monsters and earn herself the highest prestige of honor. Now all she needed was for a way to harness this power. What they didn’t know wouldn’t hurt, besides she was helping Papyrus for free. At the very least, she could make the most of it, as long as she didn’t harm the fat stupid skeleton in the process. The only problem was that the womb was getting in the way. She wished she could just get rid of it but she feared Papyrus would retaliate by going after Undyne so she would just have to work around the inconvenience and make do. In the end, who knows, it might even be beneficial to her research.

…..

 The world around was a black abyss of emptiness. No sound, breeze, color, nothing…

 Sans wandered aimlessly through the darkness, in search of something, anything. He was alone, and dare he say scared. Heh, his brother would ridicule him right about now if he saw Sans acting so pathetic. He hated being alone, but he hated being around others even more. It was a winless situation.

 Pushing forward, he continued through the void. He couldn’t tell if he was making progress but it was a lot better than just sitting around idly waiting for something he knew wouldn’t come.

 After nearly an hour of nothing remotely changing, Sans was growing frustrated. Where was he and why was it so dark? The area was so silent, one could hear a pin drop… that is if sound even traveled. As far as Sans could tell, he couldn’t even hear his own footsteps, so sound probably didn’t exist in this vacuum of empty space.

 Deciding to rest his sore body, he slumped to a sitting position but he didn’t feel like he was actually sitting on anything. More like he was just floating. The feeling was unsettling to say the least.

 Feeling distress sink in, Sans antsy hands set to work at chipping away at his left forearm. The pain helped calm his frantic mind and he relaxed ever so slightly at the familiarity of it. At least he could still feel something.

“Really~ you’ve only been here an hour and you’re already losing your mind?” Sans lurched to his feet, his soul pounded in his ribcage and his breathing rasped out in a panic. Where had that voice come from? Why did it sound so familiar? Chills crept up along Sans spine and he shivered in fear. He should feel relieved to have someone or something break the silence, but his instincts flared to life and screamed at him to run. He didn’t understand it, but he also didn’t question it. He broke off into a sprint. He had never run so fast in his life, but deep down, he dreaded what would happen if he were caught.

  
“A daring move to run, but you cannot escape the void, nor can you escape me. Just give up and let me help you.” The voice sounded sickly sweet and it made him feel even less inclined to stick around.

“Run little cherry. See what good that does you.”

 Sans slid to a stop. What was he doing? Running wasn’t helping. He was just tiring himself out. The voice had been following him the enter time, and hadn’t once sounded winded. It’s not running with him, no… it’s more like its latched onto him and he is just wasting energy, not to mention looking incredibly stupid.

  
“Done already?” The stranger mocked.

“Not quite. Show yourself!”

 The space making up the void seemed to thicken and the pressure in the air weighed down. Within the darkness, the walls and ceiling started to peel away. Even the surface beneath his feet started to wriggle and turn to mush before it pulled out from under him to a single conjoined spot where all of it turned into a black glob. The goo pulled together forming a droopy figure wearing a long wispy barely recognizable lab coat. The face of the figure was skeletal in appearance with cracks spread over the skull and across its eyes. Sans skull erupted into pain as images flashed through his brain once he realized he recognized this figure from somewhere. He envisioned himself strapped to an examination table having syringes of chemicals injected directly into his soul. His shrieked out at the ghostly memories of pain

“It’s so good to see you again.”

“Gaster…” He glared down at the oozing monster with disgust. How could he ever forget the bastard who’d forcefully raped and experimented on him? Gaster had even used his brother as a bargaining chip to keep him docile and compliant.

“I see you’ve been busy… and oh, what is that additional soul I sense… is that a child?”

 Folding his arms around his stomach protectively, he watched Gaster careful, keeping full awareness of his movements.

“Why so serious? I just wanna chat and it’s not like you have anywhere to go.” Sans flinched with unease as Gaster’s grin stretched across his face.

“Stay away from me and better yet, stay away from my child.” The doctor snickered at the comment and took a step forward. Sans snarled at Gaster in warning but the scientist carried on unhindered by the threat.

 Summoning a Gaster Blaster for protection, he fired off a blast of energy but the magic slipped through Gaster’s nearly incorporeal form.

“Oh you really shouldn’t have done that.” Sans bolted away again but black tendrils snagged his ankles, sending him toppling forward. Just before he came face first with the floor, the tendrils stopped his descend and lifted him off of the ground. He struggled in vain to break free from their grasp but more sprung up to curl around his bones and hold him in place. Bringing the smaller skeleton down to eye level, Gaster grabbed his jaw before leaning in to trail his tongue over the other’s teeth. Sans shuddered in disgust. He’d thought his days of spreading his legs for the scientist were over!

“I’ve missed you. Now be a good boy and don’t fight me. We wouldn’t want something to happen to your child, now would we?” Sans stilled in horror at the implications. If he didn’t cooperate, then Gaster would harm his child, just as Papyrus had done in his dream.

 Whimpering in defeat, he went limp in the tentacles.

“That’s it, good boy. Open real wide for me.” Sans did as he was told and unhinged his jaw.. Smirking with victory, Gaster clanked their teeth together before sliding his tongue into the small skeleton’s mouth. Not wanting to disappoint the doctor in fears of a punishment, he summoned his own tongue and tentatively pushed it up against the other’s. Gaster groaned into the kiss and pushed forward more aggressively. Breathing heavily, the two pushed into each other feeling their arousals climbing. Slipping his hands down, he grabbed the waistband of Sans shorts and tugged them down. Yelping at the sudden loss, Sans pulled away from the kiss and crossed his legs to cover his front, but two tentacles grabbed either femur and gently tugged them apart. Unable to fight back, he slowly spread his legs wider.

“Glad to see you’re remembering your place.” Closing the remaining gap, Gaster greedily grabbed his former assistant’s pelvic bone and pushed his thumb up against the pubic arch, rubbing it in rough circles. Sans cried out at the rising pleasure, earning a satisfied grin from the doc.

“You like that huh?” The tendrils holding Sans hostage pulled his hands back while Gaster pulled his pelvis forward, forcing his back to arch. Dipping his head down, Gaster trailed his tongue along his captive’s sternum while grinding his hips into his partners. Sans moaned at the docs ministrations and his hips involuntarily pushed back. Gaster let out his own moan of approval. He could feel the beginnings of his magic forming in his pelvis.

“Make me something to fuck.” Gaster gruffly breathed out along Sans neck.

 He did as he was told and summoned a cunt. His eyes looked elsewhere, feeling ashamed as the previous royal scientist greedily watched his magic form.  

 Lifting Sans slightly higher, Gaster prod a finger at the opening. Sans shivered but remained as still as possible as the other continued to rub along the slit. Gaster caught Sans eye, making him blush and turn away. Smirking at the reaction, G pulled the slits apart for better access before diving his tongue inside. The smaller skeleton lurched in his bindings at the intrusion.

“Aaah *huff* ngh ahhh…”

“You make such sweet sounds.” Pushing in deeper, he stroked and prodded Sans’ inner walls, seeking out his sweet spot. It didn’t take him long before Sans’ hips humped upward onto the tongue and he cried out as the appendage sunk deeper and struck his G-spot.

“Aaahhhh s-shit…” His eyes watered up at the stimulation and he couldn’t control his body as he rocked in time with Gaster’s thrusts. With a powerful shudder, his walls clamped down and his fluids released.

 Purring in satisfaction, the doc drank down the release, twirling his tongue around the walls and bringing it to his mouth before shoving his tongue back in to lick the cunt clean. Sans trembled from over stimulation.

“Mine~. Your brother might be your temporary fuck buddy, but don’t forget you belong to me, and eventually I’ll get free to reclaim what’s mine.”

“N-no…” Sans breathed out unevenly as he shook his head, “I’m not yours…”

 Gaster snarled in fury and flipped Sans around with blinding speed. Sans’ head spun with the flip and before he had time to react, he felt Gaster’s tentacles thrust up into his opening all at once. Sans’ eyes watered at the painful intrusion and he tried summoning his magic to fight back but one of Gaster’s floating hands wrung around his neck and squeezed it painfully.

“I wouldn't do that if I were you…” He words were cold and furious. All previous gentleness washed away. “I’ll just have to remind you of your place.” Pressing his cock at the entrance, Sans eyes widened and he cried out. “No, No! Y-you’re gonna break me.”

“If that’s what it takes to make sure you never forget your master, then so be it!” Gaster thrusted upwards, fully seating himself inside with his wriggling summoned appendages. The friction from Sans’ walls and Gaster’s own tentacles around his cock made the scientist more primal as he growled with need and want.

“Ahhh~ Sans… so fucking tight!” Without giving Sans’ time to adjust, he started thrusting in forcefully, striking deeper with each pound of his hips. Sans bobbed on the cock and shuddered as the tentacles moved impossibly deeper, stroking his innermost walls.

  
“AHhhh, G-gaster… mmm… t-to deep…” Feeling his awareness slipping away, Sans’ relaxed into the bonds as the sensations crashed over him. Grinning lustfully at his assistants submission, he slowed his hips to rock more gently into the other’s body.

“That’s it… don’t fight me…” Gaster cooed out softly. Brushing a hand along Sans’ cheek, he smiled lovingly, “You’re so beautiful. Your brother can’t even begin to appreciate your true worth.” Sans’ twitch at the soft words and fell deeper into his foggy brain at the praise. “Your mind, body and soul are all mine. I created them after all and such a precious jewel can’t be treasured and valued by anyone except me.”

Sans wanted to protest, to make a retort, but he couldn’t find his voice beyond the moans that slipped out. He belonged to no one!

 Feeling the urge to come again, Sans moaned out. “Ahn, hah…ah…AH!” Gaster quickened his pace and his chest rumbled with pride as his assistant came undone by his hands. “Cum for me.” Sans gave one last sharp cry as he released for a second time before his mind was swallowed up by the darkness, and he slipped off into unconsciousness.

 The doctor rooted himself inside the smaller skeleton as his release coating Sans inside, soaking it all the way through and marking him as his. Breathing heavily, he rocked his hips a few times to be sure he’d filled Sans’ with every last drop of his cum before he pulled out with a squelch. Lowering Sans’ to his arms, he cradled him against his chest and dispelled his tentacles.

  
  He stared down at his still assistant’s face, and smiled possessively, but as his eyes trailed lower to Sans’ belly, his expression darkened. “It seems my other failed creation decided to taint my precious treasure..… but this child could prove useful in the future… I am already itching to get back into the lab. I’d love nothing more than to run a few tests and experiments, but alas, that must wait… for now… you must rest.” Prying his eyes away from the womb, he stroked a finger along Sans’ cheeks. “Till next time…” Sans form faded as his mind slipped out of the void, back to his body.

 


End file.
